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Subject[PATCH v7 2/4] powerpc: Refactor kexec functions to move arch independent code to ima
Date
The functions ima_get_kexec_buffer() and ima_free_kexec_buffer(),
that handle carrying forward the IMA measurement logs on kexec for
powerpc do not have architecture specific code, but they are currently
defined for powerpc only.

Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to IMA
subsystem. A later patch in this series will use these functions for
carrying forward the IMA measurement log for ARM64.

With the above refactoring arch/powerpc/kexec/ima.c contains only
functions used when CONFIG_IMA_KEXEC is enabled. Update Makefile
in arch/powerpc/kexec to include arch/powerpc/kexec/ima.c only
when CONFIG_IMA_KEXEC is enabled.

Move ima_dump_measurement_list() and ima_add_kexec_buffer() to
a new file namely ima_kexec_fdt.c in IMA. Update
security/integrity/ima/Makefile to include ima_kexec_fdt.c only
when CONFIG_IMA_KEXEC is enabled.

Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
arch/powerpc/include/asm/ima.h | 3 -
arch/powerpc/kexec/Makefile | 7 +-
arch/powerpc/kexec/ima.c | 56 ---------
security/integrity/ima/Makefile | 1 +
security/integrity/ima/ima_kexec.c | 154 +++++++------------------
security/integrity/ima/ima_kexec_fdt.c | 136 ++++++++++++++++++++++
6 files changed, 182 insertions(+), 175 deletions(-)
create mode 100644 security/integrity/ima/ima_kexec_fdt.c

diff --git a/arch/powerpc/include/asm/ima.h b/arch/powerpc/include/asm/ima.h
index 6355a85a3289..8975f5e0cab8 100644
--- a/arch/powerpc/include/asm/ima.h
+++ b/arch/powerpc/include/asm/ima.h
@@ -6,9 +6,6 @@

struct kimage;

-int ima_get_kexec_buffer(void **addr, size_t *size);
-int ima_free_kexec_buffer(void);
-
#ifdef CONFIG_IMA_KEXEC
int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
size_t size);
diff --git a/arch/powerpc/kexec/Makefile b/arch/powerpc/kexec/Makefile
index 4aff6846c772..f54a9dbff4c8 100644
--- a/arch/powerpc/kexec/Makefile
+++ b/arch/powerpc/kexec/Makefile
@@ -9,12 +9,7 @@ obj-$(CONFIG_PPC32) += relocate_32.o

obj-$(CONFIG_KEXEC_FILE) += file_load.o ranges.o file_load_$(BITS).o elf_$(BITS).o

-ifdef CONFIG_HAVE_IMA_KEXEC
-ifdef CONFIG_IMA
-obj-y += ima.o
-endif
-endif
-
+obj-$(CONFIG_IMA_KEXEC) += ima.o

# Disable GCOV, KCOV & sanitizers in odd or sensitive code
GCOV_PROFILE_core_$(BITS).o := n
diff --git a/arch/powerpc/kexec/ima.c b/arch/powerpc/kexec/ima.c
index 2b790230ea15..4fadd8d16891 100644
--- a/arch/powerpc/kexec/ima.c
+++ b/arch/powerpc/kexec/ima.c
@@ -30,61 +30,6 @@ static int get_addr_size_cells(int *addr_cells, int *size_cells)
return 0;
}

-/**
- * ima_get_kexec_buffer - get IMA buffer from the previous kernel
- * @addr: On successful return, set to point to the buffer contents.
- * @size: On successful return, set to the buffer size.
- *
- * Return: 0 on success, negative errno on error.
- */
-int ima_get_kexec_buffer(void **addr, size_t *size)
-{
- int ret, len;
- unsigned long tmp_addr;
- size_t tmp_size;
- const void *prop;
-
- prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
- if (!prop)
- return -ENOENT;
-
- ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
- if (ret)
- return ret;
-
- *addr = __va(tmp_addr);
- *size = tmp_size;
-
- return 0;
-}
-
-/**
- * ima_free_kexec_buffer - free memory used by the IMA buffer
- */
-int ima_free_kexec_buffer(void)
-{
- int ret;
- unsigned long addr;
- size_t size;
- struct property *prop;
-
- prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL);
- if (!prop)
- return -ENOENT;
-
- ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
- if (ret)
- return ret;
-
- ret = of_remove_property(of_chosen, prop);
- if (ret)
- return ret;
-
- return memblock_free(addr, size);
-
-}
-
-#ifdef CONFIG_IMA_KEXEC
/**
* arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
*
@@ -177,4 +122,3 @@ int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node)

return 0;
}
-#endif /* CONFIG_IMA_KEXEC */
diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile
index 67dabca670e2..0c440870a4e9 100644
--- a/security/integrity/ima/Makefile
+++ b/security/integrity/ima/Makefile
@@ -14,3 +14,4 @@ ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o
ima-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o
ima-$(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) += ima_asymmetric_keys.o
ima-$(CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS) += ima_queue_keys.o
+ima-$(CONFIG_IMA_KEXEC) += ima_kexec_fdt.o
diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index 121de3e04af2..987e464be889 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -7,131 +7,65 @@
* Mimi Zohar <zohar@linux.vnet.ibm.com>
*/

-#include <linux/seq_file.h>
#include <linux/vmalloc.h>
#include <linux/kexec.h>
+#include <linux/of.h>
+#include <linux/memblock.h>
+#include <linux/libfdt.h>
+#include <linux/ima.h>
#include "ima.h"

-#ifdef CONFIG_IMA_KEXEC
-static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
- unsigned long segment_size)
+/**
+ * ima_get_kexec_buffer - get IMA buffer from the previous kernel
+ * @addr: On successful return, set to point to the buffer contents.
+ * @size: On successful return, set to the buffer size.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+static int ima_get_kexec_buffer(void **addr, size_t *size)
{
- struct ima_queue_entry *qe;
- struct seq_file file;
- struct ima_kexec_hdr khdr;
- int ret = 0;
-
- /* segment size can't change between kexec load and execute */
- file.buf = vmalloc(segment_size);
- if (!file.buf) {
- ret = -ENOMEM;
- goto out;
- }
-
- file.size = segment_size;
- file.read_pos = 0;
- file.count = sizeof(khdr); /* reserved space */
-
- memset(&khdr, 0, sizeof(khdr));
- khdr.version = 1;
- list_for_each_entry_rcu(qe, &ima_measurements, later) {
- if (file.count < file.size) {
- khdr.count++;
- ima_measurements_show(&file, qe);
- } else {
- ret = -EINVAL;
- break;
- }
- }
-
- if (ret < 0)
- goto out;
-
- /*
- * fill in reserved space with some buffer details
- * (eg. version, buffer size, number of measurements)
- */
- khdr.buffer_size = file.count;
- if (ima_canonical_fmt) {
- khdr.version = cpu_to_le16(khdr.version);
- khdr.count = cpu_to_le64(khdr.count);
- khdr.buffer_size = cpu_to_le64(khdr.buffer_size);
- }
- memcpy(file.buf, &khdr, sizeof(khdr));
-
- print_hex_dump(KERN_DEBUG, "ima dump: ", DUMP_PREFIX_NONE,
- 16, 1, file.buf,
- file.count < 100 ? file.count : 100, true);
-
- *buffer_size = file.count;
- *buffer = file.buf;
-out:
- if (ret == -EINVAL)
- vfree(file.buf);
- return ret;
+ int ret, len;
+ unsigned long tmp_addr;
+ size_t tmp_size;
+ const void *prop;
+
+ prop = of_get_property(of_chosen, FDT_PROP_IMA_KEXEC_BUFFER, &len);
+ if (!prop)
+ return -ENOENT;
+
+ ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
+ if (ret)
+ return ret;
+
+ *addr = __va(tmp_addr);
+ *size = tmp_size;
+ return 0;
}

-/*
- * Called during kexec_file_load so that IMA can add a segment to the kexec
- * image for the measurement list for the next kernel.
- *
- * This function assumes that kexec_mutex is held.
+/**
+ * ima_free_kexec_buffer - free memory used by the IMA buffer
*/
-void ima_add_kexec_buffer(struct kimage *image)
+static int ima_free_kexec_buffer(void)
{
- struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE,
- .buf_min = 0, .buf_max = ULONG_MAX,
- .top_down = true };
- unsigned long binary_runtime_size;
-
- /* use more understandable variable names than defined in kbuf */
- void *kexec_buffer = NULL;
- size_t kexec_buffer_size;
- size_t kexec_segment_size;
int ret;
+ unsigned long addr;
+ size_t size;
+ struct property *prop;

- /*
- * Reserve an extra half page of memory for additional measurements
- * added during the kexec load.
- */
- binary_runtime_size = ima_get_binary_runtime_size();
- if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE)
- kexec_segment_size = ULONG_MAX;
- else
- kexec_segment_size = ALIGN(ima_get_binary_runtime_size() +
- PAGE_SIZE / 2, PAGE_SIZE);
- if ((kexec_segment_size == ULONG_MAX) ||
- ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) {
- pr_err("Binary measurement list too large.\n");
- return;
- }
+ prop = of_find_property(of_chosen, FDT_PROP_IMA_KEXEC_BUFFER, NULL);
+ if (!prop)
+ return -ENOENT;

- ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer,
- kexec_segment_size);
- if (!kexec_buffer) {
- pr_err("Not enough memory for the kexec measurement buffer.\n");
- return;
- }
+ ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
+ if (ret)
+ return ret;

- kbuf.buffer = kexec_buffer;
- kbuf.bufsz = kexec_buffer_size;
- kbuf.memsz = kexec_segment_size;
- ret = kexec_add_buffer(&kbuf);
- if (ret) {
- pr_err("Error passing over kexec measurement buffer.\n");
- return;
- }
-
- ret = arch_ima_add_kexec_buffer(image, kbuf.mem, kexec_segment_size);
- if (ret) {
- pr_err("Error passing over kexec measurement buffer.\n");
- return;
- }
+ ret = of_remove_property(of_chosen, prop);
+ if (ret)
+ return ret;

- pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
- kbuf.mem);
+ return memblock_free(addr, size);
}
-#endif /* IMA_KEXEC */

/*
* Restore the measurement list from the previous kernel.
diff --git a/security/integrity/ima/ima_kexec_fdt.c b/security/integrity/ima/ima_kexec_fdt.c
new file mode 100644
index 000000000000..186051467e5b
--- /dev/null
+++ b/security/integrity/ima/ima_kexec_fdt.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2016 IBM Corporation
+ *
+ * Authors:
+ * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
+ * Mimi Zohar <zohar@linux.vnet.ibm.com>
+ */
+
+#include <linux/seq_file.h>
+#include <linux/vmalloc.h>
+#include <linux/kexec.h>
+#include <linux/of.h>
+#include <linux/memblock.h>
+#include <linux/libfdt.h>
+#include <linux/ima.h>
+#include "ima.h"
+
+static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
+ unsigned long segment_size)
+{
+ struct ima_queue_entry *qe;
+ struct seq_file file;
+ struct ima_kexec_hdr khdr;
+ int ret = 0;
+
+ /* segment size can't change between kexec load and execute */
+ file.buf = vmalloc(segment_size);
+ if (!file.buf) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ file.size = segment_size;
+ file.read_pos = 0;
+ file.count = sizeof(khdr); /* reserved space */
+
+ memset(&khdr, 0, sizeof(khdr));
+ khdr.version = 1;
+ list_for_each_entry_rcu(qe, &ima_measurements, later) {
+ if (file.count < file.size) {
+ khdr.count++;
+ ima_measurements_show(&file, qe);
+ } else {
+ ret = -EINVAL;
+ break;
+ }
+ }
+
+ if (ret < 0)
+ goto out;
+
+ /*
+ * fill in reserved space with some buffer details
+ * (eg. version, buffer size, number of measurements)
+ */
+ khdr.buffer_size = file.count;
+ if (ima_canonical_fmt) {
+ khdr.version = cpu_to_le16(khdr.version);
+ khdr.count = cpu_to_le64(khdr.count);
+ khdr.buffer_size = cpu_to_le64(khdr.buffer_size);
+ }
+ memcpy(file.buf, &khdr, sizeof(khdr));
+
+ print_hex_dump(KERN_DEBUG, "ima dump: ", DUMP_PREFIX_NONE,
+ 16, 1, file.buf,
+ file.count < 100 ? file.count : 100, true);
+
+ *buffer_size = file.count;
+ *buffer = file.buf;
+out:
+ if (ret == -EINVAL)
+ vfree(file.buf);
+ return ret;
+}
+
+/*
+ * Called during kexec_file_load so that IMA can add a segment to the kexec
+ * image for the measurement list for the next kernel.
+ *
+ * This function assumes that kexec_mutex is held.
+ */
+void ima_add_kexec_buffer(struct kimage *image)
+{
+ struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE,
+ .buf_min = 0, .buf_max = ULONG_MAX,
+ .top_down = true };
+ unsigned long binary_runtime_size;
+
+ /* use more understandable variable names than defined in kbuf */
+ void *kexec_buffer = NULL;
+ size_t kexec_buffer_size;
+ size_t kexec_segment_size;
+ int ret;
+
+ /*
+ * Reserve an extra half page of memory for additional measurements
+ * added during the kexec load.
+ */
+ binary_runtime_size = ima_get_binary_runtime_size();
+ if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE)
+ kexec_segment_size = ULONG_MAX;
+ else
+ kexec_segment_size = ALIGN(ima_get_binary_runtime_size() +
+ PAGE_SIZE / 2, PAGE_SIZE);
+ if ((kexec_segment_size == ULONG_MAX) ||
+ ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) {
+ pr_err("Binary measurement list too large.\n");
+ return;
+ }
+
+ ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer,
+ kexec_segment_size);
+ if (!kexec_buffer) {
+ pr_err("Not enough memory for the kexec measurement buffer.\n");
+ return;
+ }
+
+ kbuf.buffer = kexec_buffer;
+ kbuf.bufsz = kexec_buffer_size;
+ kbuf.memsz = kexec_segment_size;
+ ret = kexec_add_buffer(&kbuf);
+ if (ret) {
+ pr_err("Error passing over kexec measurement buffer.\n");
+ return;
+ }
+
+ ret = arch_ima_add_kexec_buffer(image, kbuf.mem, kexec_segment_size);
+ if (ret) {
+ pr_err("Error passing over kexec measurement buffer.\n");
+ return;
+ }
+
+ pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
+ kbuf.mem);
+}
--
2.28.0
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